CHEMICAL EMBRYOLOGY: TECHNOLOGIES FOR MANIPULATING AND VISUALIZING DEVELOPMENT[unreadable] Abstract[unreadable] The emergence of pattern during embryogenesis requires dynamic control of gene function with[unreadable] spatiotemporal precision. Genetic screens and transgenic models have revealed many of the molecular[unreadable] mechanisms that regulate this transformation, and the completion of multiple genome sequencing projects has[unreadable] provided a comprehensive list of developmental genes. Our efforts to understand embryonic patterning at the[unreadable] molecular and systems levels, however, have been limited by current technologies for studying embryological[unreadable] processes. New methods for controlling and visualizing gene function in vivo are needed. In this application[unreadable] we describe synthetic probes that will enable the detection of endogenous RNAs or tagged proteins in live[unreadable] organisms, with at least picomolar sensitivity. In particular, we will develop reagents that couple gene[unreadable] expression with lanthanide luminescence and utilize them to interrogate the molecular mechanisms of[unreadable] zebrafish embryogenesis. The proposed reagents build upon our expertise in synthetic chemistry and[unreadable] zebrafish embryology, and they complement reverse-genetic technologies previously developed by our[unreadable] laboratory. Using these chemical tools, developmental biologists will be able to simultaneously observe gene[unreadable] function and morphogenesis in real time, providing an unprecedented mechanistic view of embryogenesis.